Nicotine is an alkaloid present in the Solanaceae (nightshade) as well as an important component of tobacco. Nicotine is addictive or causes dependence, one of the most difficult drug addictions to get rid of that people find difficult to restrain from it. Repeated use of nicotine also increases heart rate and raises blood pressure and reduces appetite. Large dose of nicotine can cause vomiting and nausea, and even death in severe cases. Tobacco usually contains nicotine which makes smokers unable to quit smoking. However, current methods of smoking cessation generally employ nicotine-substitution method. Poor control still cannot reduce dependence on nicotine.
Clinical use of 0.15% cytisine aqueous solution for intramuscular or intravenous injections can treat reflex apnea induced by surgeries and various traumas, shock and neonatal asphyxia. Recent research reveals that this class of alkaloids also has many other pharmacological effects such as anti-arrhythmia, anti-microbial infection, anti-ulcer, elevation of white blood cell. In particular, the strong anti-cancer activity of these compounds can be used to produce smoking cessation medicine, emergency medicine and cough suppressants.
Cytisine has been sold across Eastern Europe under the trademark TABEX® as smoking cessation medicine since 1964. The use of cytisine in oral atomized liquids (electronic cigarette liquids) to substitute nicotine takes effect in getting rid of or not relying on nicotine. Current smoking cessation products, including electronic cigarettes, use nicotine to satisfy craving. However, nicotine is also extracted from tobacco and that the original meaning of smoking cessation is lost. Therefore, relapse of cigarette exists.
Oral nicotine-substituted cytisine atomized liquid, or known as electronic cigarette atomized liquid, is a popular alternative to cigarettes. Formulations and preparation process of electronic cigarette liquid, and its functions in healthcare have been reported in various literatures and patents. Chinese patent No. 200910310536.2 discloses an atomized liquid of an electronic simulated cigarette, a typical essence- and flavoring-formulated product, which comprises 25-90 parts of polyethylene glycol, 9-50 parts of propylene glycol and 0.3-52 parts of taste regulator. Chinese patent No. 200910104922.6 discloses an electronic cigarette atomized liquid, comprising 3-5% m/v of tobacco extract, 3-5% m/v of tobacco essence, 0-3% m/v of nicotine, 0.2-1% m/v of stabilizer, 3-8% m/v of thickening agent, 5-10% m/v of purified water, 50-70% m/v of propylene glycol, and optionally codeine phosphate, chlorpheniramine, or the like. Despite the use of tobacco extract, it is still a product formulated from tobacco extract and other essences and flavorings to imitate the taste of cigarettes. As more and more smokers adopt electronic cigarettes instead of cigarettes, some shortages of taking electronic cigarettes become more and more obvious. Smokers generally reflect that, although electronic cigarettes and cigarettes share similar shapes, textures and smoke, their aroma and taste are relatively different. In particular, they find difficult to adopt or get used to the aroma and taste of essence- and flavoring-formulated products. In addition, a common problem reflected by smokers is that aroma components of current electronic cigarette liquids are difficult to retain for a long time. The best ones can only be kept for about half a year, which “taste of cigarette” becomes very light or even gone. These shortages greatly affect the quality of electronic cigarette and restrict the prevalence and popularity of electronic cigarette.